overheating vs severe overheating
Thread Starter
Drifting
Joined: Apr 2007
Posts: 1,294
Likes: 16
From: Carson City Nevada
overheating vs severe overheating
I have heard this quote numerous times..."all big blocks overheat..." But my "new" L89 engine doesn't just overheat, it severely overheats. It has a new BB Dewitts radiator, a flex fan, an electric 2500 cfm aux fan behind the radiator, an overflow tank...everything we could think of to cool this beast down. New hoses, new thermo (160 degree) new 15# rad cap, new everything really. If I stop, like for gas and turn engine off, it really climbs fast. It seems to stay at 160 to 180 as long as I keep moving, but as soon as I make that first stop, even for a traffic light, off it goes and it won't come back down till I stop and let it cool off. I once stopped for over two hours, got back in, went less than a mile and it overheated to boil over. I've read as many overheating threads as I could find on the forum...tried most "remedys"...still no luck...even went to "water wetter" that's how desperate I am. Forget parades...I just want to get through regular stop and go traffic without blowing up. Anybody like to throw some more suggestions as to what else I can look for? Thanks guys...Nick
Le Mans Master
Joined: Mar 2005
Posts: 7,631
Likes: 11
From: Rocklin California
First thing that comes to mind is your electric fan isn't working or not enough amps to spin it fas at idle. That is where I would start. Also make sure if it's a puller that it in fact is pulling air. And if in front as a pusher that it is pushing air. NOT backward! 
I removed my flex fan for the puller electric fan and it made all the difference.
Also make sure if it's a puller that it in fact is pulling air. And if in front as a pusher that it is pushing air. NOT backward! I removed my flex fan for the puller electric fan and it made all the difference.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
The brass rad GM designed for BB Sting Rays has less cooling capacity than the aluminum SB rad. Most aluminum BB rads have more.
Make sure your shroud is sealed top and bottom and that both side tanks are sealed front and rear.
Remove any lower splash shields that restrict air flow from the engine compartment around the exhausts.
Install a lower rubber shroud seal in the gap to the cross member to prevent air being recirculated to the front of the rad when standing in traffic
Standard checks like correct vacuum advance sourced at the manifold, and good hoses and thermostats are assumed
use an infrared "gun" thermometer to get the upper and lower rad temp differences. Also, what are the exhaust manifold temps when the engine is hot?
Make sure your shroud is sealed top and bottom and that both side tanks are sealed front and rear.
Remove any lower splash shields that restrict air flow from the engine compartment around the exhausts.
Install a lower rubber shroud seal in the gap to the cross member to prevent air being recirculated to the front of the rad when standing in traffic
Standard checks like correct vacuum advance sourced at the manifold, and good hoses and thermostats are assumed
use an infrared "gun" thermometer to get the upper and lower rad temp differences. Also, what are the exhaust manifold temps when the engine is hot?
Last edited by magicv8; Jul 21, 2010 at 04:23 PM.
Burning Brakes
Joined: Mar 2005
Posts: 1,231
Likes: 34
From: Ontario
How about a little more info on the engine, Bore, heads planed, cam, distributer curve ect. You didn't mention the water pump being changed ? There is lots of info in the archives and if you have done all of the common fixes there must be something missing in the puzzle.
Bill Purdy
Bill Purdy
Melting Slicks
Joined: Jan 2002
Posts: 2,132
Likes: 71
From: SOUTH SHORE Massachusetts
ever have the block flushed out????? ever look in the radiator when the car is running and check to see if the water is flowing decently? ( of course I am talking about when the rad is cool not hot) ever check to see if the elect fan is going in the correct direction? pulling not pushing? is it a stock water pump? has the block been bored before? with the setup as you described it should not do what you say its doing. I would use a 180 thermostat too as I feel it lets the water stay in the rad longer to cool down before recirculating...good luck
Le Mans Master
Joined: Nov 2008
Posts: 5,691
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From: columbus oh
if everything is dialed in correctly as you say...it's time to look for something internal like a head gasket....use a p&g block check tool and follow the directions....the clue to this is the fact it will not cool down on it's own no matter how you drive it....this is presuming the water pump and hoses and timing etc....etc....are all up to snuff....could be as simple as no head bolt sealer or improper bolt torque too....
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Race Director
Joined: Dec 2004
Posts: 10,332
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From: PARADISE
St. Jude Donor '09-'11-'12-'13-'14
Take the rad cap off and run the engine until it opens the thermostat. Look for bubbles in the puke tank. If it bubbles, chances are a blown head gasket.
Good Luck,
Dave
Good Luck,
Dave
Race Director
Joined: Feb 2007
Posts: 15,479
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From: northern california
C2 of Year Finalist (track prepared) 2019
A friend of mine has one in his '63 that has a 572 or thereabouts. He drives this car in the summer in California's central valley with no overheating issues.
Jim
Thread Starter
Drifting
Joined: Apr 2007
Posts: 1,294
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From: Carson City Nevada
Wow...great responses everybody...let me address a few...
Kensmith, it's a new electric fan, pulling 18 amps, 2500 cfm, puller mounted on correct side of rad. You can feel the air moving from front to back really well. But it took running it for 30 minutes with the engine off to cool it from 240 to 180.
Magicv8, I will try a few of those ideas.
63split63, it's a brand new high volume water pump from Summit...seems to be working as it should...water is moving fine, just gets really, really hot.
midyearvette...Hi Peter...yep, everything else is up to snuff, but I'm interested in hearing your points on no head bolt sealer or improper bolt torque...can you expand my knowledge on those? Thanks...
Donald31176...I'll double check that.
MikeM...it's a completly newly built engine...no California involved here...
Claysmoker...Dave, I like your idea and I'll try that...want to take over this build since you have so much free time on your hands?
So where's the finished project?
Time to post this and go try a few of these things out...Nick
Kensmith, it's a new electric fan, pulling 18 amps, 2500 cfm, puller mounted on correct side of rad. You can feel the air moving from front to back really well. But it took running it for 30 minutes with the engine off to cool it from 240 to 180.
Magicv8, I will try a few of those ideas.
63split63, it's a brand new high volume water pump from Summit...seems to be working as it should...water is moving fine, just gets really, really hot.
midyearvette...Hi Peter...yep, everything else is up to snuff, but I'm interested in hearing your points on no head bolt sealer or improper bolt torque...can you expand my knowledge on those? Thanks...
Donald31176...I'll double check that.
MikeM...it's a completly newly built engine...no California involved here...
Claysmoker...Dave, I like your idea and I'll try that...want to take over this build since you have so much free time on your hands?
So where's the finished project?Time to post this and go try a few of these things out...Nick
Race Director
Joined: Jan 2003
Posts: 17,721
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From: Central Arkansas
Changing this makes a world of difference. I watched the temp gage on my aluminum head 427 drop significantly just from this change.
Thread Starter
Drifting
Joined: Apr 2007
Posts: 1,294
Likes: 16
From: Carson City Nevada
Oops...sorry Frank...Dennis rightly corrected me on your name...I couldn't bring it to mind and looked at your public profile to remind myself...but looked at MidYearRoadster's instead...what a moroon....I couldn't even get that part right...apologies to both and thanks Dennis for the pm...
Race Director
Joined: Dec 2004
Posts: 10,332
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From: PARADISE
St. Jude Donor '09-'11-'12-'13-'14
Not done yet Nick, but I have put a hundred miles or so on it. Just trying to tidy up the loose ends(like hanging the doors)and hope they will be done by HAN.
BTW: Jim would certainly know about the bolt sealant, I doubt this is the problem. If it's not a blown head gasket, I would look at timing/mixture issues. Where are the initial and total timing numbers set?
BTW: Jim would certainly know about the bolt sealant, I doubt this is the problem. If it's not a blown head gasket, I would look at timing/mixture issues. Where are the initial and total timing numbers set?
Racer
Joined: Jul 2004
Posts: 468
Likes: 12
From: Pleasant Hill CA
cooling
timing make a huge diffrerence on the temp of the motor? what is your timing set at?? the more you advance it the cooler it usually will run.
also make sure u have spring in your bottom radiator hose? also
check to see how far your fan is inside your shroud?? your fan blades
should be at least half way inside your shroud. also what themostat are you running?? i run a 160 degree thermostat in my car and it
really helps keep it from heating up?? every little thing you can do
will help as they all work together to help keep it cool. good luck.
also make sure u have spring in your bottom radiator hose? also
check to see how far your fan is inside your shroud?? your fan blades
should be at least half way inside your shroud. also what themostat are you running?? i run a 160 degree thermostat in my car and it
really helps keep it from heating up?? every little thing you can do
will help as they all work together to help keep it cool. good luck.
Former Vendor
Joined: Jan 2000
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From: Brighton
Melting Slicks
Joined: May 2001
Posts: 2,159
Likes: 64
From: Nichols Florida
Make sure the balancer it correctly marked for tdc, same for the pointer on the block. Use a dial indicator on #1 piston to see if it is aligned at tdc when timing mark on balancer is aligned with pointer.
Tyler
Tyler
Race Director
Joined: Sep 2005
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From: Birmingham Mi
Talk to Mr. DeWitt, he is across the table!
Rick
Le Mans Master
Joined: Mar 2005
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From: Rocklin California
